A Millimeter-Wave Microcalorimeter

A new type of microcalorimeter has been developed at the Electrotechnical Laboratory as the national millimeter-wave power standard in Japan. This is the single load type calorimeter using semiconductor Peltier thermoelements and a standard bolometer mount. The experiment has been successful in the frequency region of 35 kMc, and this method is considered to be suitable for millimeter-wave regions. By this method and equipment, the effective efficiency of the standards mount is determined precisely. The errors in this microcalorimetric technique are investigated with the aid of heat flow analysis and auxiliary experiments. As a result of this, the absolute accuracy of the power measurement in the millimeter wave region (35 kMc) is evaluated with high accuracy (better than ± 0.5 per cent).